Production of 5-methyl-n-aryl-2-pyrrolidone and 5-methyl-n-alkyl-2-pyrrolidone by reductive amination of levulinic acid with nitro compounds

ABSTRACT

This invention relates to a process for producing 5-methyl-N-aryl-2-pyrrolidone, 5-methyl-N-cycloalkyl-2-pyrrolidone, and 5-methyl-N-alkyl-2-pyrrolidone by reductive amination of levulinic acid with nitro compounds utilizing a metal catalyst, which is optionally supported.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of Ser. No. 10/396,050 filed on Mar.24, 2003, now U.S. Pat. No. 6,818,593.

FIELD OF INVENTION

This invention relates to a process for producing5-methyl-N-aryl-2-pyrrolidone, 5-methyl-N-cycloalkyl-2-pyrrolidone, and5-methyl-N-alkyl-2-pyrrolidone by reductive amination of levulinic acidwith nitro compounds utilizing a metal catalyst, which is optionallysupported.

BACKGROUND OF THE INVENTION

Levulinic acid is a well-known product of hexose acid hydrolysis, andcan be inexpensively obtained from cellulose feedstocks. Consequently,it is an attractive starting material in producing many useful 5-carboncompounds and their derivatives. For example, N-cyclohexyl-2-pyrrolidoneis used as a solvent or intermediate in many industrial applications,including the electronics industry (photo-resist stripping solutions),industrial cleaners, oil/gas well maintenance, and fiber dyeing.N-[2-hydroxyethyl]-2-pyrrolidone is useful in industrial cleaning,printing inks, and gasoline and oil additives. N-octyl-2-pyrrolidone isuseful, for example, in the manufacture of agricultural products, as adetergent and dispersant, in industrial and metal cleaners, in printinginks and in fiber dyeing.

Emmert (Ber. d. deutschen chemischen Gesellschaft, 1907,40: 912)describes a process for producing 5-methyl-1-phenyl-pyrrolidone bysimultaneous electrolytic reduction of levulinic acid and nitrobenzene.The reaction was carried out for 5-22.5 hr at a quantity of current andtemperature of 90 ampere-hours and 16° C. to 33° C., respectively. Thisprocess is complex and yields only the phenyl derivative. U.S. Pat. No.3,337,585 discloses a process for preparing5-methyl-1-alkyl-2-pyrrolidone utilizing levulinic acid and a primaryalkyl amine at a temperature of 50° C. to 350° C. under carbon monoxideat a pressure of 1.0 to 101 MPa. Additional potential primary aminesinclude alkylene diamines, aryl amines and cycloalkyl amines. Compoundscontaining NO₂ groups are not used. U.S. Pat. No. 3,235,562 describes avapor phase process for producing lactams by the reductive amination ofoxo carboxylic acid compounds. Volatile alkyl or aryl primary amines maybe used; nitro compounds are not used. Candeloro and Bowie (Aust. J.Chem., 1978, 31:2031-2037) describe a process for producing5-methyl-2,3-dihydro-1-H-benzazepin-2-one and5-(2-methyl-5-oxo-1-phenylpyrrolidin-2-yl)-4-oxo-N-phenylpentanamide byreacting levulinic acid with aniline under a nitrogen atmosphere.

An efficient and low cost process for the production of aryl, alkyl andcycloalkyl pyrrolidones would be advantageous.

SUMMARY OF THE INVENTION

The present invention is a novel, one-step process for convertinglevulinic acid and nitro compounds to aryl, alkyl and cycloalkylpyrrolidones as set forth in greater detail below in the presence ofcatalysts. Specifically, the present invention relates to a process forpreparing 5-methyl-N-aryl-2-pyrrolidone (III),5-methyl-N-cycloalkyl-2-pyrrolidone (IV), or a mixture thereof, whichcomprises the step of contacting the compound levulinic acid (I) with anaryl nitro compound (II) in the presence of a catalyst and hydrogen gas;

wherein R₁ is an aromatic group having from 6 to 30 carbons and R₂ is afully or partially reduced derivative of R₁, and wherein5-methyl-N-aryl-2-pyrrolidone (III), 5-methyl-N-cycloalkyl-2-pyrrolidone(IV), or a mixture thereof, may comprise 100% by weight of the totalproduct formed, or wherein additional products may be produced.

The catalyst useful in the process of the invention is selected frommetals from the group consisting of palladium, ruthenium, rhenium,rhodium, iridium, platinum, nickel, cobalt, copper, iron, osmium;compounds thereof; and combinations thereof.

The present invention also relates to a process for preparing5-methyl-N-alkyl-2-pyrrolidone (VI) which comprises the step ofcontacting levulinic acid (I) with an alkyl nitro compound (V) in thepresence of a catalyst and hydrogen gas;

wherein R₃ is an alkyl group having from 1 to 30 carbons and R₃ may beC₁-C₃₀ unsubstituted or substituted alkyl, C₁-C₃₀ unsubstituted orsubstituted alkenyl, C₁-C₃₀ unsubstituted or substituted alkynyl, C₃-C₃₀unsubstituted or substituted cycloalkyl, or C₃-C₃₀ unsubstituted orsubstituted cycloalkyl containing at least one heteroatom, and wherein5-methyl-N-alkyl-2-pyrrolidone (VI) may comprise 100% by weight of thetotal product formed, or wherein additional products may be produced.

The catalyst useful in this process of the invention is selected frommetals from the group consisting of palladium, ruthenium, rhenium,rhodium, iridium, platinum, nickel, cobalt, copper, iron, osmium;compounds thereof; and combinations thereof.

DETAILED DESCRIPTION OF THE INVENTION

By “levulinic acid” is meant the compound having the following formula:

By “aryl nitro compound” is meant the compound having the formula R—NO₂wherein R is an aromatic group.

By “5-methyl-N-aryl-2-pyrrolidone” is meant the compound having thegeneral formula below wherein R₁ is an aryl group having from 6 to 30carbons:

By “5-methyl-N-cycloalkyl-2-pyrrolidone” is meant the compound havingthe general formula below wherein R₂ is a cycloalkyl group having from 6to 30 carbons:

By “5-methyl-N-alkyl-2-pyrrolidone” is meant the compound having thegeneral formula below wherein R₃ is C₁-C₃₀ unsubstituted or substitutedalkyl, C₁-C₃₀ unsubstituted or substituted alkenyl, C₁-C₃₀ unsubstitutedor substituted alkynyl, C₃-C₃₀ unsubstituted or substituted cycloalkyl,or C₃-C₃₀ unsubstituted or substituted cycloalkyl containing at leastone heteroatom:

By “catalyst” is meant a substance that affects the rate of the reactionbut not the reaction equilibrium, and emerges from the processchemically unchanged.

By “metal catalyst” is meant a catalyst that is comprised of at leastone metal, at least one Raney metal, compounds thereof or combinationsthereof.

By “promoter” is meant an element of the Periodic Table that is added toenhance the physical or chemical function of the catalyst. The promotercan also be added to retard undesirable side reactions and/or affect therate of the reaction.

By “metal promoter” is meant a metallic compound that is added toenhance the physical or chemical function of a catalyst. The metalpromoter can also be added to retard undesirable side reactions and/oraffect the rate of the reaction.

By “fully or partially reduced derivative” of an aryl compound is meanta compound that can be derived from the parent compound by saturating orreducing one or more of the unsaturated bonds in the aromatic ring.Unsaturated compounds are compounds that contain one or more carbon tocarbon double or triple bonds. For example, a fully reduced derivativeof a phenyl group is a cyclohexyl group.

This invention relates to the synthesis of 5-methyl-N-aryl-2-pyrrolidone(III), 5-methyl-N-cycloalkyl-2-pyrrolidone (IV) or a mixture thereof,from a reaction between levulinic acid (I) and an aryl nitro compound(II) in the presence of a catalyst and hydrogen;

wherein R₁ is an aromatic group having from 6 to 30 carbons and R₂ is afully or partially reduced derivative of R₁, and wherein5-methyl-N-aryl-2-pyrrolidone (III), 5-methyl-N-cycloalkyl-2-pyrrolidone(IV), or a mixture thereof, may comprise 100% by weight of the totalproduct formed, or wherein additional products may be produced.

In addition, this invention relates to the synthesis of5-methyl-N-alkyl-2-pyrrolidone (VI) from a reaction between levulinicacid (I) and an alkyl nitro compound (II) in the presence of a catalystand hydrogen;

wherein R₃ is an alkyl group having from 1 to 30 carbons and R₃ may beC₁-C₃₀ unsubstituted or substituted alkyl, C₁-C₃₀ unsubstituted orsubstituted alkenyl, C₁-C₃₀ unsubstituted or substituted alkynyl, C₃-C₃₀unsubstituted or substituted cycloalkyl, or C₃-C₃₀ unsubstituted orsubstituted cycloalkyl containing at least one heteroatom, and wherein5-methyl-N-alkyl-2-pyrrolidone (VI) may comprise 100% by weight of thetotal product formed, or wherein additional products may be produced.

A catalyst, with or without a support, may be present in the processesof the invention to effect the amination reactions. A promoter mayoptionally be used to aid the reactions. The promoter can be a metal.

The processes of the present invention may be carried out in batch,sequential batch (i.e., a series of batch reactors) or in continuousmode in any of the equipment customarily employed for continuous process(see for example, H. S. Fogler, Elementary Chemical ReactionEngineering, Prentice-Hall, Inc., N.J., USA). The condensate waterformed as the product of the reaction is removed by separation methodscustomarily employed for such separations, such as distillation.

The aryl and cycloalkyl groups represented by R₁ and R₂ in Formulas(II), (III) and (IV) preferably have from 6 to 30 carbons. Morepreferably, the aryl and cycloalkyl groups represented by R₁ and R₂ inFormulas (II), (III) and (IV) have from 6 to 12 carbons. An example of apreferred embodiment of Formula (II) is nitrobenzene; thus Formulas(III) and (IV) would be 5-methyl-N-phenyl-2-pyrrolidone and5-methyl-N-cyclohexyl-2-pyrrolidone, respectively. The unsubstituted orsubstituted alkyl or cycloalkyl group represented by R₃ in Formulas (V)and (VI) preferably has from 1 to 30 carbons. More preferably theunsubstituted or substituted alkyl or cycloalkyl group represented by R₃in Formulas (V) and (VI) has from 1 to 12 carbons.

In the processes of the invention, a molar ratio of nitro compound tolevulinic acid or its salt, of from about 0.01/1 to about 100/1, ispreferred at the start of the reaction. A molar ratio of from about0.3/1 to about 5/1 is further preferred at the start of the reaction.

A temperature range of from about 25° C. to about 300° C. is preferredfor the processes of the invention. A temperature range of from about75° C. to about 200° C. is further preferred.

A pressure range of from about 0.3 MPa to about 20 MPa is employed forthe processes of the invention. A pressure range of from about 1.3 MPato about 7.6 MPa is preferred.

The reactions of the present invention can be performed in non-reactingsolvent media such as water, alcohols, ethers, and pyrrolidones.Alternatively, the excess of aryl or alkyl nitro compound can also actas the solvent medium.

The catalyst useful in the invention is a substance that affects therate of the reaction but not the reaction equilibrium, and emerges fromthe process chemically unchanged. A chemical promoter generally augmentsthe activity of a catalyst. The promoter herein may be incorporated intothe catalyst during any step in the chemical processing of the catalystconstituent. The chemical promoter generally enhances the physical orchemical function of the catalyst agent, but can also be added to retardundesirable side reactions.

The processes of the invention involve reductive amination of levulinicacid with nitro compounds, which is effected in the presence of acatalyst. The principal component of the catalyst useful herein isselected from metals from the group consisting of palladium, ruthenium,rhenium, rhodium, iridium, platinum, nickel, cobalt, copper, iron,osmium; compounds thereof; and combinations thereof.

A promoter may be used optionally in the reactions of the presentinvention. The promoter herein may be incorporated into the catalystduring any step in the chemical processing of the catalyst constituent.Suitable promoters for the processes of the invention include metalsselected from tin, zinc, copper, gold, silver, and combinations thereof.The preferred metal promoter is tin. Other promoters that can be usedare elements selected from Group 1 and Group 2 of the Periodic Table.

The catalyst used in the process may be supported or unsupported. Asupported catalyst is one in which the active catalyst agent isdeposited on a support material by a number of methods, such asspraying, soaking or physical mixing, followed by drying, calcination,and if necessary, activation through methods such as reduction oroxidation. Materials frequently used as a support are porous solids withhigh total surface areas (external and internal), which can provide highconcentrations of active sites per unit weight of catalyst. The catalystsupport may enhance the function of the catalyst agent. A supportedmetal catalyst is a supported catalyst in which the catalyst agent is ametal.

A catalyst that is not supported on a catalyst support material is anunsupported catalyst. An unsupported catalyst may be platinum black or aRaney catalyst. The expression “Raney catalyst” as used herein refers tocatalysts that have a high surface area due to selectively leaching analloy containing the active metal(s) and a leachable metal (usuallyaluminum). Raney catalysts have high activity due to the higher specificarea and allow the use of lower temperatures in hydrogenation reactions.The active metals of Raney catalysts include nickel, copper, cobalt,iron, rhodium, ruthenium, rhenium, osmium, iridium, platinum, palladium;compounds thereof; and combinations thereof. The name Raney catalyst isnot meant to denote any particular source of the material.

Promoter metals may also be added to the base Raney metals to affectselectivity and/or activity of the Raney catalyst. Promoter metals forRaney catalysts may be selected from transition metals from Groups IIIAthrough VIIIA, IB and IIB of the Periodic Table of the Elements.Examples of promoter metals include chromium, molybdenum, platinum,rhodium, ruthenium, osmium, and palladium, typically at about 2% byweight of the total metal.

The catalyst support useful herein can be any solid, inert substanceincluding, but not limited to, oxides such as silica, alumina andtitania; barium sulfate; calcium carbonate and carbons. The catalystsupport can be in the form of powder, granules, pellets, or the like.

A preferred support material of the invention is selected from the groupconsisting of carbon, alumina, silica, silica-alumina, silica-titania,titania, titania-alumina, barium sulfate, calcium carbonate, strontiumcarbonate, compounds thereof and combinations thereof. Supported metalcatalysts can also have supporting materials made from one or morecompounds. More preferred supports are carbon, titania and alumina.Further preferred supports are carbons with a surface area greater than100 m²/g. A further preferred support is carbon with a surface areagreater than 200 m²/g. Preferably, the carbon has an ash content that isless than 5% by weight of the catalyst support; the ash content is theinorganic residue (expressed as a percentage of the original weight ofthe carbon) which remains after incineration of the carbon.

Commercially available carbons which may be used in this inventioninclude those sold under the following trademarks: Bameby & Sutcliffe™,Darco™, Nuchar™, Columbia JXN™, Columbia LCK™, Calgon PCB™, Calgon BPL™,Westvaco™, Norit™ and Barnaby Cheny NB™. The carbon can also becommercially available carbon such as Calsicat C, Sibunit C, or Calgon C(commercially available under the registered trademark Centaur(R)).

In the processes of the invention, the preferred content of the metalcatalyst in the supported catalyst is from about 0.1% to about 20% ofthe supported catalyst based on metal catalyst weight plus the supportweight. A more preferred metal catalyst content range is from about 1%to about 10% of the supported catalyst. A further preferred metalcatalyst content range is from about 3% to about 7% of the supportedcatalyst.

Combinations of metal catalyst and support system may include any one ofthe metals referred to herein with any of the supports referred toherein. Preferred combinations of metal catalyst and support includepalladium on carbon, palladium on calcium carbonate, palladium on bariumsulfate, palladium on alumina, palladium on titania, platinum on carbon,platinum on alumina, platinum on silica, iridium on silica, iridium oncarbon, iridium on alumina, rhodium on carbon, rhodium on silica,rhodium on alumina, nickel on carbon, nickel on alumina, nickel onsilica, rhenium on carbon, rhenium on silica, rhenium on alumina,ruthenium on carbon, ruthenium on alumina and ruthenium on silica.

Further preferred combinations of metal catalyst and support includepalladium on carbon, palladium on alumina, palladium on titania,platinum on carbon, platinum on alumina, rhodium on carbon, rhodium onalumina, ruthenium on carbon and ruthenium on alumina.

The levulinic acid useful in the processes of the invention may beobtained using traditional chemical routes or obtained from biobased,renewable cellulosic feedstocks. Utilization of bio-derived levulinicacid is likely to reduce the cost of manufacture of the compounds hereinrelative to conventional methods.

The compounds produced by the processes of the invention displayproperties that are useful in diverse applications. N-alkyl pyrrolidoneswith alkyl chains up to about 8 carbons function as aprotic chemicalsolvents with a lower toxicity profile than other solvents. The carbonchains of N-lower pyrrolidones are not long enough to allow micelleformation in water; thus these compounds do not exhibit significantsurfactant properties. N-alkyl pyrrolidones with alkyl groups of aboutC₈ to C₁₄ exhibit surfactant properties, and pyrrolidones with longerN-alkyl chains act as complexing agents. The surface-active propertiesof alkyl pyrrolidones, such as solubility, wetting, viscosity building,emulsifying and complexing are described in U.S. Pat. No. 5,294,644.N-alkyl pyrrolidones can also be used for concentrating colloidalparticles. Due to their solvent, surfactant and complexing properties,pyrrolidones are very useful in the manufacture of pharmaceuticals,personal care products, and industrial, agricultural and householdchemicals and products.

The pyrrolidones produced by the processes of the invention are usefulin preparing pharmaceutical products for use on humans, animals,reptiles, and fish. The pyrrolidones disclosed herein are particularlyuseful in topical formulations, such as ointments, creams, lotions,pastes, gels, sprays, aerosols, lotions, shampoos, foams, creams, gels,ointments, salves, milks, sticks, sprays, balms, emulsions, powders,solid or liquid soaps, or oils. Pyrrolidones, such as5-methyl-2-pyrrolidones, can be used to enhance the transdermalpenetration of active components into human or animal tissues andsystems. Pyrrolidones can also act as solubilizers to enhance thesolubility of a therapeutic agent in the carrier system.

The pyrrolidones produced by the processes of the invention may also beincorporated into matrix systems, such as patches, for the transdermaladministration of, for example, an antimicrobial, a hormone, or ananti-inflammatory. The methods of preparation of pharmaceuticalcompositions as are commonly practiced in the pharmaceutical industryare useful with the processes of the invention. For discussion of suchmethods, see, for example, Remington's Pharmaceutical Sciences (A RGennaro, ed., 20th Edition, 2000, Williams & Wilkins, PA) incorporatedherein by reference.

The pyrrolidones made by the processes of the invention may be used assolvents or surfactants in liquid, gel or aerosol cleaning compositionsfor cleaning a wide range of surfaces, including textiles, such asclothing, fabrics and carpets, and hard surfaces, such as glass, metal,ceramics, porcelain, synthetic plastics and vitreous enamel. Thepyrrolidones may also be used in formulations for disinfecting hardsurfaces, such as in the household, or in institutional or hospitalenvironments, or the surface of skin, or fabric surfaces, or in the foodpreparation, restaurant or hotel industries. In addition, cleaningcompositions are useful for the removal of industrial soils, such asdirt, grease, oil, ink and the like. The pyrrolidones may also be usedas solvents in compositions for cleaning, solvating, and/or removingplastic resins or polymers from manufactured articles or manufacturingequipment.

In addition to pyrrolidones, other components may be included incleaning compositions. These additional components include nonionicsurfactants, anionic surfactants, cationic surfactants, amphotericsurfactants and solvents. Illustrative nonionic surfactants are alkylpolyglycosides, such as Glucopon (Henkel Corporation), ethylene oxideand mixed ethylene oxide/propylene oxide adducts of alkylphenols, theethylene oxide and mixed ethylene oxide/propylene oxide adducts of longchain alcohols or of fatty acids, mixed ethylene oxide/propylene oxideblock copolymers, esters of fatty acids and hydrophilic alcohols, suchas sorbitan monooleate, alkanolamides, and the like.

Illustrative anionic surfactants are the soaps, higher alkylbenzenesulfonates containing from 9 to 16 carbons in the higher alkyl group ina straight or branched chain, C₈-C₁₅ alkyl toluene sulfonates, C₈-C₁₅alkyl phenol sulfonates, olefin sulfonates, paraffin sulfonates, alcoholand alcoholether sulfates, phosphate esters, and the like.

Illustrative cationic surfactants include amines, amine oxides,alkylamine ethoxylates, ethylenediamine alkoxylates such as theTetronic® series from BASF Corporation, quaternary ammonium salts, andthe like.

Illustrative amphoteric surfactants are those which have both acidic andbasic groups in their structure, such as amino and carboxyl radicals oramino and sulfonic radicals, or amine oxides and the like. Suitableamphoteric surfactants include betaines, sulfobetaines, imidazolines,and the like.

Illustrative solvents include glycols, glycol ethers, aliphaticalcohols, alkanolamines, pyrrolidones and water.

Such surfactants and solvents are described, for example, inMcCutcheon's (2002), Volume 1 (Emulsifiers and Detergents) and Volume 2(Functional Materials), The Manufacturing Confectioner Publishing Co.,Glen Rock, N.J.

Cleaning compositions may also include additional components, such aschelating agents, corrosion inhibitors, antimicrobial compounds,buffering and pH adjusting agents, fragrances or perfumes, dyes, enzymesand bleaching agents.

N-alkyl-2-pyrrolidones are useful in cleaning and stripping formulationswhich are used to remove (or strip) a photoresist film (or other similarorganic polymeric material film) or layer from a substrate, or to removeor clean various types of plasma-etch residues from a substrate.N-alkyl-2-pyrrolidones are also useful as surfactants in cleaningformulations for removing solder pastes from printing applicators andcircuit assemblies.

N-alkyl-2-pyrrolidones, such as 5-methyl-N-octyl-2-pyrrolidone and5-methyl-N-dodecyl-2-pyrrolidone, may be included as components in inkjet inks in order to improve resistance to highlighter smear whenprinted into an image, lead to an even print (minimize the degree ofbanding) and impart an improved waterfast resistance and/or a better dryor wet rub property. 2-Pyrrolidones, such as5-methyl-N-cyclohexyl-2-pyrrolidone or 5-methyl-N-methyl-2-pyrrolidone,may also be used as solvents in the preparation of hot melt or phasechange inks for color printing.

The pyrrolidones made by the processes of the invention can also beutilized in the manufacture of agrochemicals, including but not limitedto herbicides, insecticides, fungicides, bactericides, nematicides,algicides, mulluscicides, virucides, compounds inducing resistance toplants, repellants of birds, animals and insects, and plant growthregulators, or mixtures thereof. The method of manufacture comprisescontacting an agrochemically effective agent as known to persons skilledin the art with at least one of the pyrrolidones produced by any of themethods of the invention. The agrochemical composition can optionallycomprise additional auxilary components as are commonly used in theagrochemical industry.

Pyrrolidones, such as 5-methyl-N-methyl pyrrolidone and5-methyl-N-cyclohexyl pyrrolidone, can be used as water insoluble polarco-solvents to solubilize water insoluble pesticides and otheragrochemicals and increase the effective amount of active ingredient.N-alkyl pyrrolidones, preferably N—C₃₋₁₅ alkyl pyrrolidones, inparticular 5-methyl-N-octyl pyrrolidone and5-methyl-N-dodecylpyrrolidone, can be used as nonionic surfactants thataid as emulsifiers. Plant growth regulators are used to improve theeconomic yield of agricultural plants. 5-Methyl-N-octyl pyrrolidone and5-methyl-N-dodecyl pyrrolidone can be utilized as solvents in emulsionscontaining plant growth regulators.

In addition, pyrrolidones can be utilized in liquid or aerosolformulations for dermal application of insect repellants by humans;examples include mosquito and tick repellants. Manufacture of suchinsect repellants comprises contacting an effective amount of at leastone insect-repelling agent with at least one product produced using atleast one process of the invention.

Pyrrolidones, such as 5-methyl-N-methyl-2-pyrrolidone, can also be usedin antimicrobial formulations for the preservation of animal silage.

5-Methyl-N-alkyl-2-pyrrolidones can also be used as part of a moreenvironmentally-conscious method for dry-cleaning clothing that includesa surfactant and densified carbon dioxide in place of traditionalsolvents.

In addition, 5-methyl-2-pyrrolidones can be used as components in aprotective composition for use on painted surfaces, such as cars. Thepyrrolidones function to wet the surface and promote spreadibility ofthe protectant.

Different plastic materials are often not miscible, resulting inproducts that exhibit insufficient mechanical properties. Monomeric andpolymeric 5-methyl-pyrrolidone-containing compounds can be used ascompatibilizers for plastic compositions; the compatibilizers attachthemselves to the interface between the polymers involved, or penetrateinto the polymers, thereby improving the adhesion between the polymersand enhancing mechanical properties.

5-Methyl-N-pyrrolidones can also be used as compatibilizers in therefrigeration and air conditioning industries. Transitioning fromchlorofluorocarbon to hydrofluorocarbon refrigerants has necessitatedthe use of a new class of lubricants due to immiscibility withconventional lubricants such as mineral oil, poly α-olefin andalkylbenzene. However the new class of lubricants is expensive and alsovery hygroscopic. Absorption of water leads to acid formation andcorrosion of the refrigeration system, as well as the formation ofsludges. The lack of solubility of the hydrofluorocarbons in theconventional lubricants results in a highly viscous lubricant in thenon-compressor zones, and results in insufficient lubricant return tothe compressor. This can eventually result in a number of problems,including the compressor overheating and seizing and insufficient heattransfer in the refrigeration system. Compatibilizers solubilize thepolar halogenated hydrocarbon refrigerant and the conventional non-polarlubricant in the non-compressor zones, which results in efficient returnof lubricant to the compressor zone. Compatibilizers may include the5-methyl-N-alkyl- and 5-methyl-N-cycloalkyl-2-pyrrolidones.

Pyrrolidones can also be used as fuel and lubricant additives. Forexample, N-alkyl-2-pyrrolidones can be used as detergents anddispersants in fuel additive compositions to keep valves, carburetorsand injection systems clean, thereby improving the combustioncharacteristics and reducing deposits, thus reducing air pollutingemissions. In addition, 5-methyl-N-methyl-2-pyrrolidone can be used toremove unsaturated hydrocarbons from raw lube distillates or deasphaltedresidual lube stocks to produce solvent-refined base oils as lubricants.

Methods for the preparation of cleaning, stripping, agrochemical andplastic formulations are well known to persons skilled in the art.Similarly, methods for the preparation of insect repellants, ink jetinks, protective formulations for paint, fuel additives and lubricants,refrigeration and air conditioning lubricants, and for dry cleaning arewell known in the art. Pyrrolidones can act as solvents, surfactants,dispersants, detergents, emulsifiers, viscosity builders and complexingagents in these formulations. Appropriate pyrrolidones are selectedbased on standard screening procedures for product performance.Additional components, such as pharmaceutical or agrochemical activeagents or colorants, may be added to specific formulations as the mainfunctional component; the nature of the functional component orcomponents would be determined by the specific use. Auxiliarycomponents, which enhance or are critical to the efficacy of theformulation, may also be added. Auxiliary components may includesolvents or cosolvents, thickeners, antioxidants, spreading agents,preservatives, adhesives, emulsifiers, defoamers, humectants,dispersants, surfactants, suitable carriers, matrix systems, deliveryvehicles, fragrances, salts, esters, amides, alcohols, ethers, ketones,acids, bases, alkanes, silicone, evaporation modifiers, paraffins,aliphatic or aromatic hydrocarbons, chelating agents, gases foraerosols, propellants or for dry cleaning, oils and water. Appropriateauxiliary components for the uses described herein are known to personsskilled in the art.

The following examples are illustrative of the invention. Examples 1 to18 are actual examples; Examples 19 to 24 are prophetic.

EXAMPLES

The following abbreviations are used:

-   -   ESCAT-XXX: Series of catalysts provided by Engelhard Corp.        (Iselin, N.J.).    -   JM-AXXXX, JM-XXXX-SA, JM-XXXX, JM-BXXXX: Series of catalysts        from Johnson Matthey, Inc. (W. Deptford, N.J.).    -   SCCM: Standard cubic centimeters per minute    -   GC: Gas chromatography    -   GC-MS: Gas chromatography-mass spectrometry

For catalyst preparation a commercially available support such ascarbon, alumina, silica, silica-alumina or titania was impregnated byincipient wetness with a metal salt. The catalyst precursors used wereNiCl₂.6H₂O (Alfa Chemical Co., Ward Hill, Mass.), Re₂O₇ (Alfa ChemicalCo.), PdCl₂ (Alfa Chemical Co.), RuCl₃.xH₂O (Aldrich Chemical Co.,Milwaukee, Wis.), H₂PtCl₆ (Johnson Matthey, Inc.) and RhCl₃.xH₂O (AlfaChemical Co.). The samples were dried and reduced at 300-450° C. underH₂ for 2 hours.

Raney catalysts are available from W.R. Grace & Co. (Columbia, Md.), andnitropropane, nitrobenzene, dioxane and levulinic acid are availablefrom Fisher Scientific (Chicago, Ill.).

Catalyst Preparation: 5% Pt on Acid Washed Calsicat Carbon

In a 150 ml beaker, a solution was made up of 4.5 ml 0.3 M H₂PtCl₆ with4.0 ml deionized H₂O. To the beaker were added 4.75 g Calsicat AcidWashed Carbon (12×20 mesh, dried at 120° C. overnight). The slurry wasallowed to stand at room temperature for 1 hr with occasional stirring,followed by drying at 120° C. overnight with frequent stirring (untilfree flowing).

In an alumina boat, in a quartz lined tube furnace, the catalyst waspurged with 500 SCCM N₂ at room temperature for 15 min and then with 100SCCM He at room temperature for 15 min. The catalyst was heated to 150°C. and held at 150° C. under He for 1 hr. At this point, 100 SCCM H₂were added and the sample was held at 150° C. under He and H₂ for 1 hr.The temperature was increased to 300° C. and the catalyst was reduced at300° C. under He—H₂ for 8 hrs. The H₂ was stopped, the sample was heldat 300° C. under He for 30 min and then cooled to room temperature inflowing He. The catalyst was finally passivated in 1.5% O₂ in N₂ at 500SCCM for 1 hr at room temperature and weighed 4.93 g when unloaded.

Additional catalysts used in the present invention were preparedfollowing a similar procedure.

Batch Reduction of Levulinic Acid to 5-Methyl-N-Aryl-2-Pyrrolidone and5-Methyl-N-Cycloalkyl-2-Pyrrolidone

To a 5 ml pressure vessel was added 50 gm of catalyst, and 1 gm of asolution containing 35 wt % levulinic acid, 31% aryl nitro compound and34% dioxane. The vessel was sealed, charged with 5.52 MPa hydrogen andheated to 150° C. for 4 hours. The pressure was maintained at 5.52 MPaduring the course of the reaction. At the end of the reaction, thevessel was rapidly cooled in ice, vented and an internal GC standard ofmethoxyethylether was added. The solution was separated by pipette fromthe catalyst and analyzed by GC-MS using an HP 6890 (Agilent; Palo Alto,Calif.) equipped with a FFAP 7717 (30 meter) column. The results setforth in the tables below are based on area %.

The examples described below were performed according to a similarprocedure under the conditions indicated for each example.

Examples 1-4 Preparation of 5-Methyl-N-Propyl-2-Pyrrolidone (PrMP) usingLevulinic Acid (LA) and 1-Nitropropane (NP)

The reaction was carried out for 4 hours at a temperature of 150° C. anda pressure of 5.52 MPa. The results are set forth in the followingtable.

Feedstock LA PrMP Ex. Catalyst/ Ratio Conversion Selectivity No.Support^(a) Feedstock (wt %) (%) (%) 1 5% Pd/C LA/NP/ 35/27/38 91.2 52.9(ESCAT-142) Dioxane 2 5% Pt/C LA/NP/ 35/27/38 95.8 66.4 (ESCAT-248)Dioxane 3 5% Rh/C LA/NP/ 35/27/38 86.7 29.0 (JM-11761) Dioxane 4 5% Ru/CLA/NP/ 35/27/38 98.5 24.8 (ESCAT-440) Dioxane ^(a)Source forcommercially available catalyst/support is in parentheses.

Examples 5-8 Preparation of 5-Methyl-N-Phenyl-2-Pyrrolidone (PhMP) and5-Methyl-N-Cyclohexyl-2-Pyrrolidone (CyHMP) using Levulinic Acid (LA)and Nitrobenzene (NB)

The reaction was carried out for 4 hours at a temperature of 150° C. anda pressure of 5.52 MPa. The results are set forth in the followingtable.

Feedstock LA CyHMP PhMP Catalyst/ Ratio Conversion SelectivitySelectivity Ex. No. Support^(a) Feedstock (wt %) (%) (%) (%) 5 5% Pd/CLA/NB/ 35/31/34 89.1 15.2 20.2 (ESCAT- Dioxane 142) 6 5% Pt/C LA/NB/35/31/34 82.5 4.0 23.7 (ESCAT- Dioxane 248) 7 5% Rh/C LA/NB/ 35/31/3488.4 11.1 9.6 (JM-11761) Dioxane 8 5% Ru/C LA/NB/ 35/31/34 97.5 4.2 8.6(ESCAT- Dioxane 440) ^(a)Source for commercially availablecatalyst/support is in parentheses.

Examples 9-18 Preparation of 5-Methyl-N-Phenyl-2-Pyrrolidone (PhMP) and5-Methyl-N-Cyclohexyl-2-Pyrrolidone (CVHMP) using Levulinic Acid (LA)and Nitrobenzene (NB)

The reaction was carried out for 6 hours at a temperature of 150° C. anda pressure of 5.52 MPa. The results are set forth in the followingtable.

Feedstock CyHMP PhMP Ex. No. Catalyst/Support^(a) Feedstock Ratio (wt %)Yield (%) Yield (%) 9 5% Pd/C LA/NB/Dioxane 30/32/38 16.7 36.4(JM-A11108-5) 10 5% Pd/C LA/NB/Dioxane 30/32/38 30.7 22.2 (ESCAT-142) 115% Ru/C LA/NB/Dioxane 30/32/38 3.4 3.3 (JM-141060-SA) 12 5% Rh/CLA/NB/Dioxane 30/32/38 9.3 18.7 (JM-11761) 13 5% Pt/C LA/NB/Dioxane30/32/38 3.1 47.8 (JM-B21142-5) 14 5% Pt/C LA/NB/Dioxane 30/32/38 6.846.2 (ESCAT-248) 15 5% Pt/Al₂O₃ LA/NB/Dioxane 30/32/38 2.7 24.8(ESCAT-294) 16 5% Pd/Al₂O₃ LA/NB/Dioxane 30/32/38 2.4 46.4 (JM-A22117-5)17 5% Ru/Al₂O₃ LA/NB/Dioxane 30/32/38 7.3 12.6 (Aldrich) 18 5% Rh/Al₂O₃LA/NB/Dioxane 30/32/38 39.0 10.4 (Aldrich) ^(a)Source for commerciallyavailable catalyst/support is in parentheses.

Example 19

Pharmaceutical Formulations A) Topical Formulation: Solubilizer(diethylene glycol monoethyl ether) 2.0% to 50% Skin permeation enhancer2.0% to 50% (N-hydroxyethyl-2-pyrrolidone) Emulsifier 2.0% to 20%Emollient (propylene glycol) 2.0% to 20% Preservative 0.01 to 0.2%Active agent   0 to 25% Carrier Balance B) Cream: Phase 1: Polyethyleneglycol and  5.0% ethylene glycol palmitostearate Caprilic/caprictriglycerides  5.0% Oleoyl macrogolglycerides (Labrafil M 1944CS)  4.0%Cetyl alcohol  5.5% PPG-2 myristyl ether propionate (Crodamol PMP)  6.0%5-methyl-N-hydroxyethyl-2-pyrrolidone  2.0% Phase 2: Xanthan gum  0.3%Purified water   55% Phase 3: Propylene glycol  1.0% Methylparaben 0.18%Propylparaben 0.02% Phase 4: Naftifine hydrochloride (antifungal)  1.0%Diethylene glycol monoethyl ether (Transcutol)   15%Procedure:

Xanthan gum is dispersed in water and allowed to stand. Phase 1components and phase 2 components are separately heated to 75° C.; phase1 is mixed into phase 2 under high speed agitation. The temperature ismaintained at 75° C. while stirring for 10 min. The mixture is thenslowly cooled while stirring at low speed. At 40° C., phase 3 is added.Naftifine is then mixed well into the Transcutol, and the mixture isadded to the cream, mixed well and the cream is cooled to roomtemperature.

C) Transdermal Patch Formulation: Ketoprofen 0.3% Polysorbate 80 0.5%5-Methyl-N-methyl-2-pyrrolidone 1.0% 5-Methyl-N-ethyl-2-pyrrolidone 2.0%PEG 400  10% CMC-Na 4.0% Na-polyacrylate 5.5% Sanwet 1M-1000PS 0.5%Polyvinyl alcohol 1.0% PVP/VA copolymer 3.0%

Example 20

Cleaning Compositions A) Grease Removal Formulation: Water  89%Potassium carbonate  1.0% Potassium bicarbonate  5.0%5-Methyl-N-octyl-2-pyrrolidone  2.5% Deriphatec 151-C (Henkel Corp.) 2.5% B) Oil-in-Water Emulsion in Aerosol Form: Crillet 45 (Croda) 3.30% Monamulse DL 1273 (Mona Industries, Inc.)  3.30%5-Methyl-N-dodecyl-2-pyrrolidone  5.50% Denatured absolute ethanol15.40% 100 AG/F3 (CSR Ltd.) Norpar 15 (Exxon)  5.50% Deionized water44.10% Butane 16.95% Propane  5.95% C) All-Purpose Liquid CleaningComposition: Neodol 91-8 (Shell)  3.5% Linear alkyl (C9-13) benzenesulfonate, Mg salt  10.5% Propylene glycol mono-t-butyl ether  4.0% Cocofatty acid  1.4% 5-Methyl-N-decyl-2-pyrrolidone  1.0% Magnesium sulfateheptahydrate  5.0% Water  74.6 D) Shower-Rinsing Composition: Glucopon225 (Henkel Corp.)  2.0% Isopropyl alcohol  2.2% Sequestrene 40 (45%,Ciba)  1.0% Fragrance  0.02% Barquat 4250Z (50%, Lonza)  0.2%5-Methyl-N-octyl-2-pyrrolidone  1.0% Water 93.58% E) DishwashingComposition: Ethanol (95%)  8.6% Alfonic 1412-A [Ethylene oxide sulfate(59.3%)]  22.5% Alfonic 1412-10  1.1% Sodium chloride  0.9%5-Methyl-N-decyl-2-pyrrolidone  7.5% Water  59.4% F) AqueousAntimicrobial Cleaning Composition: Adipic acid  0.40% Dacpon 27-23 AL(Condea; C₁₂₋₁₄ sodium alkyl  0.15% sulfate, 28% active) Isopropylalcohol  1.8% Dowanol PnB (Dow; propylene glycol  0.30% mono-N-butylether) 5-Methyl-N-octyl-2-pyrrolidone  0.4% Sodium hydroxide  0.05%Water  96.9%

An antimicrobial wipe can be made by impregnating a substrate with theabove composition; the substrate can be spunlace comprisingviscose/polyester at a ratio of 70:30 with a specific weight of 50grams/m². The composition to substrate ratio is about 2.6:1.

G) Disinfectant: Benzalkonium chloride 5.0% Sodium carbonate 2.0% Sodiumcitrate 1.5% Nonoxynol 10 2.5% 5-Methyl-N-octyl-2-pyrrolidone 5.0% Water 84% H) Anti-Parasitidal Agent (for dermal application to animals):Antiparasital agent 1 to 20% 5-Methyl-N-isopropyl-2-pyrrolidone  30%Benzyl alcohol (preservative) 3.0% Thickener 0.025-10% Colorant0.025-10% Emulsifier 0.025-10% Water Balance

Example 21

Stripping/Cleaning Formulation:

5-Methyl-N-methyl-2-pyrrolidone   30% Monoethanolamine   55% Lactic acid 5.0% Water   10%

Example 22

Ink Jet Ink:

CAB-O-JET 300 (Active)  4.0% Diethylene glycol 17.5%5-Methyl-N-octyl-2-pyrrolidone  2.5% Deionized H₂O   76%

Example 23

Agrochemical Compositions

A) Composition for the Control of Insects: Permethrin 2.0%5-Methyl-N-decyl-2-pyrrolidone 3.0% Dimethyl dipropyl naphthalene 7.0%Lauryl alcohol 5.0% Hymal 1071 (MatsumotoYushi Seiyaky, Inc.)  10%Hytenol N-08 (Daiichi Kogyo Seiyaku, Inc.) 2.0% Polyoxyethylene glycol 71% B) Pesticide Formulation: 5-Methyl-N-alkyl pyrrolidone  48% Sodiumdodecyl sulfate  12% Agrimer AL25  10% Rodeo (pesticide; Monsanto) 1.0%Water  29% C) Emulsifiable Fungicide Formulation: Kresoxin-methyl 0.5%Propylene carbonate 1.5% Aromatic petroleum distillate 150 (Exxon) 2.9%5-methyl-N-octyl-2-pyrrolidone 3.8% CaH/DDBSA [50% (Ca dodecylbenzene1.4% Sulfonate + Dodecylbenzene Sulfonic acid (5:1) in Exxon 150 WaterBalance

Example 24

Formulation for Protective Composition for Painted Automobile Surfaces:

Propylene glycol phenyl ether 2.0% 5-Methyl-N-octyl-2-pyrrolidone 0.1%Emulsified silicone: 3.0% a) dimethyl silicone (2.67%) b)amino-functional silicone (0.21%) c) silicone resin (0.12%) Water 94.9%

1. A process for preparing a cleaning composition, the processcomprising the steps of: i) preparing 5-methyl-N-alkyl-2-pyrrolidone(VI) using a process comprising the step of contacting levulinic acid(I) with an alkyl nitro compound (V) in the presence of hydrogen gas anda metal catalyst, the metal catalyst being optionally supported, and,optionally, in the presence of a solvent;

 wherein R₃ is C₁-C₃₀ unsubstituted or substituted alkyl, C₂-C₃₀unsubstituted or substituted alkenyl, C₂-C₃₀ unsubstituted orsubstituted alkynyl, C₃-C₃₀ unsubstituted or substituted cycloalkyl, orC₃-C₃₀ unsubstituted or substituted cycloalkyl containing at least oneheteroatom; and ii) contacting 5-methyl-N-alkyl-2-pyrrolidone (VI) witha compound selected from the group consisting of anionic surfactants,nonionic surfactants, cationic surfactants, amphoteric surfactants,glycols, glycol ethers, aliphatic alcohols, alkanolamines, pyrrolidones,water, and mixtures thereof.
 2. A process for preparing an ink jet inkcomposition, the process comprising the steps of: i) preparing5-methyl-N-alkyl-2-pyrrolidone (VI) using a process comprising the stepof contacting levulinic acid (I) with an alkyl nitro compound (V) in thepresence of hydrogen gas and a metal catalyst, the metal catalyst beingoptionally supported, and, optionally, in the presence of a solvent;

 wherein R₃ is C₁-C₃₀ unsubstituted or substituted alkyl, C₂-C₃₀unsubstituted or substituted alkenyl, C₂-C₃₀ unsubstituted orsubstituted alkynyl, C₃-C₃₀ unsubstituted or substituted cycloalkyl, orC₃-C₃₀ unsubstituted or substituted cycloalkyl containing at least oneheteroatom; and ii) contacting 5-methyl-N-alkyl-2-pyrrolidone (VI) withat least one colorant.
 3. A process for preparing a refrigerant or airconditioning lubricant, the process comprising the steps of: i)preparing 5-methyl-N-alkyl-2-pyrrolidone (VI) using a process comprisingthe step of contacting levulinic acid (I) with an alkyl nitro compound(V) in the presence of hydrogen gas and a metal catalyst, the metalcatalyst being optionally supported, and, optionally, in the presence ofa solvent;

 wherein R₃ is C₁-C₃₀ unsubstituted or substituted alkyl, C₂-C₃₀unsubstituted or substituted alkenyl, C₂-C₃₀ unsubstituted orsubstituted alkynyl, C₃-C₃₀ unsubstituted or substituted cycloalkyl, orC₃-C₃₀ unsubstituted or substituted cycloalkyl containing at least oneheteroatom; and ii) contacting 5-methyl-N-alkyl-2-pyrrolidone (VI) withat least one refrigerant.